All manner and variety of devices or appliances configured for the absorption of such body fluids as menses are known. Feminine napkins presently used for catamenial protection comprise absorbent pad structures which for the most part are of elongate and substantially rectangular configuration. However, the market is provided with a large variety of such napkins in different lengths, widths, and thicknesses, each of which is designated as being suitable for a particular body size or shape, for heavy or light flows, or for different age needs. In addition to the more common rectangular form, there exists a limited selection of other geometric configurations also designed to meet particular body shapes or sizes.
As a class, sanitary napkins ought to possess certain necessary attributes of absorbency, comfort and psychological as well as physiological or physical protection. Desirably, these devices also are characterized as being discreet during wear.
Sanitary napkins, including contoured sanitary napkins, such as those described in U.S. Pat. Nos. 4,397,644 and 4,079,739, are well known. Conceptualizing, sanitary napkins of this sort are typically of multilayered construction including a fluid absorbent core interposed within a backing of a fluid impermeable shield or baffle and a fluid permeable cover, the latter transmitting menstrual fluid, or the like, across its boundary to the absorbent core. As those skilled in the art will readily appreciate, the interrelationship of components is substantially more intricate; however, for purposes of basic understanding, the foregoing suffices.
The prior art has recognized the practicality of raising one or more layers of the absorbent portion of the sanitary napkin in the direction of the wearer of multilayer sanitary napkins to obtain less fluid leakage, better positioning of the sanitary napkin, and the like. U.S. Pat. No. 2,964,039 discloses a sanitary napkin wherein the napkin has a curved lengthwise configuration giving the napkin a preformed arcuate shape in the direction of its length to conform to and cover the exterior female pubic area. That patent describes sanitary napkins which have a preformed arcuate shape and have a thicker absorbent layer in the middle of the pad than at the ends.
Recognizing the benefit of increasing the amount of the absorbent component in the perineal area of the wearer, U.S. Pat. No. 3,406,689 describes a sanitary napkin comprising two separate pieces. One portion is a replaceable highly-absorbent soft contact pad which actually contacts the body of the wearer. The second portion is a back-up sanitary napkin which is worn by the wearer to keep the contact pad in place. The back-up sanitary napkin is larger and movable with respect to the contact pad and is designed to absorb any excess menstrual discharge.
U.S. Pat. No. 3,528,442 uses a secondary layer centrally located on the top layer of the primary pad. The primary pad has three layers of absorbent fluff and creped wadding and absorbent paper. A wrapping is used to attach the secondary layer to the primary pad. U.S. Pat. No. 4,433,972 offers a similar type of sanitary napkin comprising a backing sheet and a face sheet having an absorbent pad assembly sandwiched between the two sheets. The pad assembly includes two pads. The primary pad is relatively large and is made of wood fluff or similar absorbent material. The second pad is substantially diamond shaped and is of lesser dimensions than the primary pad. The second pad is seated on the primary pad.
Thus, the art has recognized the benefits of increasing the area of absorbent material near the center of the sanitary napkin. U.S. Pat. Nos. 2,331,355, 2,747,575 and 4,046,147 disclose additional means whereby a larger amount of absorbent material is present in the center of the sanitary napkin.
A different method of increasing the bulk or density of absorbent material in a sanitary napkin is described in U.S. Pat. Nos. 4,340,058 and 4,490,147 where a plurality of elongate absorbent pads, each of approximately circular cross-section, are arranged parallel to one another in a pyramid shaped bundle to obtain increased absorbency where most desired in the center of the sanitary napkin.
A sanitary napkin wherein the absorbent material in the center of the sanitary napkin gradually decreases or tapers near the end of the sanitary napkin is disclosed in U.S. Pat. No. 2,973,760. The tapering of the absorbent material is gradual instead of step-wise as was the case for much of the aforedescribed prior art.
Unlike much of the prior art where the sanitary napkin is rectangular or somewhat triangular in shape, U.S. Pat. No. 3,805,790 discloses an anatomy-conforming feminine napkin which is biconcave, that is, substantially hourglass-shaped.
Design U.S. Pat. Nos. 215,386, 236,385, 272,190 and 276,554 depict catamenial napkins wherein there is a raised portion in the center area of the napkin. The raised portions depicted are either folds in the napkin or are the result of an increased amount of absorbent material extending upward to the cover or top layer of the pad.